Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

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The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

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Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON3):

Solution:
n,m=map(int,input().split())
L=[list(map(int,input().split())) for i in range(n)]
s="row"
s1="col"
if n>m :
    L1=[[0 for i in range(n)] for j in range(m)]
    for i in range(n) :
        for j in range(m) :
            L1[j][i]=L[i][j]
    L=L1
    n,m=m,n
    s,s1=s1,s
            
w=[0 for i in range(n)]
w1=[0 for i in range(m)]
for i in range(n) :
    w[i]=min(L[i])
for i in range(m) :
    for j in range(n) :
        ma=0
        ma=max(L[j][i]-w[j],ma)
    w1[i]=ma
for i in range(n) :
    for j in range(m) :
        if L[i][j]-w[i]-w1[j]!=0 :
            print(-1)
            exit()
otv=[]
for i in range(n) :
    otv+=[s+" "+str(i+1)]*w[i]
for i in range(m) :
    otv+=[s1+" "+str(i+1)]*w1[i]
print(len(otv))
print('\n'.join(otv))